The present invention is intended to provide an appropriate and satisfactory radiator apparatus for use in a large scale motor vehicle, e.g., a two-wheeled motor vehicle which has what is termed a lateral V-type crankshaft straddle type engine.
Such vehicle usually has a water cooled engine, and as a result is also equipped with a radiator to cool down the coolant which gets heated up by the engine. This radiator is located so as to receive the full cooling effect of wind as the vehicle moves, and is placed in back of the front wheel; that is, it is fastened to the front section of the down tubes which form a part of the vehicle body frame.
It happens that, in cases where use is made of a lateral V-type crankshaft straddle type engine, with a pair of cylinders, front and rear inclined, as in large scale two-wheeled motor vehicles, part of the engine, inclined towards the front, particularly the cylinder head section, protrudes towards the front section of the down tubes, limiting the space for the installation of the radiator, and causing a problem as a result.
On the other hand, since there are tanks used for temporary storage of coolant above and below, and also due to considerations of efficiency and of construction requirements, radiators are generally front facing.
As a consequence, in the case of large scale two-wheeled motor vehicles having lateral V-type crankshaft straddle type engines, it has to date been impossible, due to restrictions on installation space, to use a large scale radiator with full cooling capabilities. Where, in order to provide for the enlargement of the radiator, a horizontal type, with the upper and lower tanks placed toward the right and left, has been selected, due to the fact that the lower middle section of the radiator core is turned upwards, and the lower section is made in a concave form, the engine section, previously mentioned, which protruded towards this concave section could fit through. However, even in such a structure there were limitations on the design of larger scale models, in particular because there were shortcomings in efficiency resulting from the fact that the radiator is made up of a large number of thin tubes aligned in a row, and, in order to carry out heat release for the heated coolant which is made to pass through these tubes, the length of the tubes varied, so that partial imbalances of coolant flow pressure would arise, making good and effective cooling infeasible.